1. Field of the Invention
The present invention relates to a connector housing for connecting a male connector and a female connector with each other with a waterproof seal therebetween and a method of manufacturing the waterproof connector housing.
2. Description of the Prior Art
In general, a ring-like packing is used as a separate part for sealing an engagement face between a male connector and a female connector. However, the work for attaching the packing to the engagement face is worrisome and the packing is liable to fall off. To eliminate these drawbacks, it is disclosed in Japanese Patent Application Laid-Open Showa 63-221568 that a ring-like packing c is integrally formed on an inner wall of a housing of a female connector as illustrated in FIG. 5, or, the ring-like packing may be formed integrally in double housings e of the male connector d as illustrated in FIG. 6. Further, in order to improve the waterproofness of the packing, a sticky material is added to a rubber material to give the packing c and c' stickiness. However, when the rubber material has stickiness, it also sticks to a metal mold. Even though surface treatment such as fluorine coating is applied to the metal mold to avoid the problem, the durability of the coating is not sufficient so that there is a difficulty in putting the method into practical use.
Further, it is disclosed in the patent application described above that fluid silicone rubber is used as material for the packing c and c'.
When synthetic rubber other than the silicone rubber is used as material for the packing, a vulcanizing agent such as sulfur, organic peroxide or the like is added for vulcanization. As a result, secondary products of the reaction are volatilized, causing electric contacts to be polluted. On the other hand, when addition-reaction silicone rubber is used, the secondary products described above are not generated, but, cyclicsiloxane remains in the fluid silicone rubber, which also causes the electric contacts to be polluted as described above. Therefore, to avoid the problem, a waterproof rubber stopper or a ring-like packing as a separate part is attached to a housing after those parts are secondarily vulcanized at 200.degree. C. or 2 hours. However, when the packing is integrally formed with the housing, the secondary vulcanization cannot be applied due to the deformation of the housing. That is, there is a problem in which when the packing is integrally formed with the housing according to predetermined vulcanizing time, injection pressure, and temperature of metal mold for vulcanizing the rubber, the housing deforms or burrs are generated on the packing form attached to the housing since the housing is made of unreinforced thermoplastic resin such as PBT, 6-nylon and 6,6-nylon.